基于环氧大豆油改性聚氨酯胶黏剂的轻质高强刨花板制备与性能研究OA

With the continuous development of the particleboard industry,its major applications have expanded beyond traditional furniture panels to emerging markets such as wall panels,large-size countertops,and tall door boards.These new applications impose higher requirements for low-density yet high-strength particleboards.To address the structural characteristics of the surface and core layers in three-layer particleboard,a synergistic double-layer polyurethane adhesive modification strategy with epoxidized soybean oil and isocyanate was proposed.Three-layer particleboards with target densities of 0.50,0.55,and 0.60 g/cm³ were manufactured from poplar(Populus sp.)particles of different geometries.In the control group,both the surface and core layers were bonded with polymeric methylene diphenyl diisocyanate(pMDI).In the development group,the surface layer was bonded with a high-strength epoxidized soybean oil-modified polyurethane adhesive(EPA),while the core layer was bonded with a lightweight foamable polyurethane adhesive(FPU).The mechanical properties,including modulus of rupture(MOR),modulus of elasticity(MOE),and internal bond strength(IB),as well as the 24 h thickness swelling and water absorption,were evaluated.In addition,scanning electron microscopy(SEM)was used to examine the microstructure and adhesive distribution in the panels,so as to elucidate the mechanisms by which the adhesives regulated panel performance.The results showed that,at all three low-density levels,the modified particleboards achieved a synergistic improvement in both weight reduction and performance enhancement.In particular,the modified particleboards with a density of 0.55 g/cm³(10％adhesive content and gradient hot pressing at 190 ℃)exhibited MOR,MOE,and IB values of 12.33 MPa,1 710 MPa,and 0.54 MPa,respectively,meeting the requirements for Type P2 particleboard specified in the Chinese national standard GB/T 4897-2015 Particleboard.Microscopic observations revealed that a three-dimensional porous cross-linked network was formed in the core layer of the modified particleboards,which was the key to achieving both low density and high strength.Overall,the synergistic double-layer pMDI-based adhesive modification strategy not only reduced pMDI consumption,but also improved the overall performance of the particleboards,thereby providing a feasible technical route for manufacturing lightweight high-strength particleboards.